Metal-containing resin particle, resin particle, electronic circuit substrate, and method of producing electronic circuit

ABSTRACT

According to one mode of the present invention, metal-containing resin particles comprising a resin containing a thermosetting resin at 50 wt % or more and having a rate of moisture absorption from 500 to 14500 ppm, and fine metal particles contained in the resin, is provided.

CROSS-REFERENCE TO THE INVENTION

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2003-435758, filed on Dec. 26,2003; the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a metal-containing resin particle, aresin particle, an electronic circuit substrate, and a method ofproducing the electronic circuit.

2. Description of the Related Art

Conventionally, when producing an electronic circuit substrate, aconductor pattern is formed by performing resist coating on a thin metalfilm, exposure, development, etching, and the like (refer to JapanesePatent Laid-open Application No. Hei 7-263841). However, this methodrequires exposure masks for respective layers, the design and productionthereof require a plenty of time and cost. Besides, when alternation,modification or the like of the exposure masks becomes necessary, agreat influence is exerted upon the time of delivery or costs of theelectronic circuit substrate.

Because of these disadvantages, a method of forming an electroniccircuit substrate by printing using electrophotography is proposedinstead of the above method. In this method, an underlying layer forelectroless plating having an arbitrary pattern is first prepared byusing electrophotography with a metal-containing resin particle. Aplating layer is formed on the underlying layer by electroless plating,and an insulating layer is formed by electrophotography using resinparticles made of resin only, so that an electronic circuit substrate isformed.

Incidentally, in order to accurately form an underlying layer and aninsulating layer by electrophotography, it is necessary to control theamount of electrostatic charge of metal-containing resin particles andresin particles. Here, considering heat resistance, thermosetting resinmainly composed of an epoxy resin is used for both the resin of themetal-containing resin particles and the resin particles containingresin only. However, since epoxy radicals are easy to absorb moisturedue to its high hydrophilic nature, there is a problem in that theelectrical resistance of the surfaces of the metal-containing resinparticles and the resin particles is lowered, and the desired amount ofelectrostatic charge is difficult to obtain.

BRIEF SUMMARY OF THE INVENTION

According to one mode of the present invention, metal-containing resinparticles comprising a resin containing a thermosetting resin at 50 wt %or more and having a rate of moisture absorption from 500 to 14500 ppm,and fine metal particles contained in the resin, is provided.

According to another mode of the present invention, resin particlescomprising a resin containing a thermosetting resin at 50 wt % or moreand having a rate of moisture absorption of 500 to 14500 ppm, isprovided.

According to still another mode of the present invention, an electroniccircuit substrate comprising a substrate, a metal-containing resin layerformed on said substrate and formed by using the metal-containing resinparticles according to claim 1, and a plating layer formed on saidmetal-containing resin layer by using metal particles of saidmetal-containing resin layer as kernels is provided.

According to yet another mode of the present invention, an electroniccircuit substrate comprising a substrate, a plating layer formed on saidsubstrate, and a resin layer formed on said plating layer, and formed byusing the resin particles according to claim 5 is provided.

According to another mode of the present invention, a method ofproducing an electronic circuit, comprising forming a metal-containingresin layer in an environment at 70% or less of relative humidity,wherein said forming of the metal-containing resin layer comprisesforming a visible image on a surface of a photoconductor on which anelectrostatic latent image is formed, by electrostatically attachingmetal-containing resin particles composed of a resin containing 50 wt %or more of a thermosetting resin and having a rate of moistureabsorption from 500 to 14500 ppm, and fine metal particles contained inthe resin, and transferring the visible image composed of themetal-containing resin particles and formed on the surface of thephotoconductor on a substrate, is provided.

According to still another mode of the present invention, a method ofproducing an electronic circuit, comprising forming a metal-containingresin layer in an environment of 70% or less in relative humidity,wherein said forming of the resin layer comprises forming a visibleimage on a surface of a photoconductor on which an electrostatic latentimage is formed, by electrostatically attaching resin particles composedof a resin containing 50 wt % or more of a thermosetting resin andhaving 500 to 14500 ppm in rate of moisture absorption, and transferringthe visible image composed of the resin particles and formed on thesurface of the photoconductor on the substrate, is provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart showing a flow of production process of anelectronic circuit substrate relating to an embodiment of the presentinvention.

FIG. 2A to FIG. 2D are schematic diagrams of production process of theelectronic circuit substrate relating to an embodiment of the presentinvention.

FIG. 3 is a view showing the operation of an underlying layer formingapparatus relating to an embodiment of the present invention.

FIG. 4 is a view showing the operation of an insulating layer formingapparatus relating to an embodiment of the present invention.

FIG. 5 is a graph showing relations between a rate of moistureabsorption of metal-containing resin particles and the amount ofelectrostatic charge of the metal-containing resin particles relating toexample 1.

FIG. 6 is a graph showing relations between a rate of moistureabsorption of resin particles and the amount of electrostatic charge ofthe resin particles relating to example 2.

FIG. 7 is a graph showing relations between time for standing still anda rate of moisture absorption of the resin particles relating to example3.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments will be explained. FIG. 1 is a flow chartshowing a flow of production process of an electronic circuit substraterelating to an embodiment of the present invention, and FIG. 2A to FIG.2D are schematic process drawings of the electronic circuit substraterelating to an embodiment of the present invention. FIG. 3 is a viewshowing operations of an underlying layer forming apparatus relating toan embodiment of the present invention, and FIG. 4 is a view showingoperations of an insulating layer forming apparatus relating to anembodiment of the present invention.

First, as shown in FIG. 1 and FIG. 2A, an underlying layer 2 forelectroless plating is formed by printing using electrophotography (step1). The underlying layer 2 can be formed by using an underlying layerforming apparatus 10 as shown in FIG. 3. Concretely, the underlyinglayer forming apparatus 10 mainly comprises a photoconductor drum 11, anelectrostatic charger 12, a laser generator and scanner 13, a developingmachine 14, a transfer printing machine 15, and a fixing apparatus 16.The underlying layer forming apparatus 10 is placed in a room R wherethe relative humidity is 70% or lower.

In order to form the underlying layer 2, while the photoconductive drum11 is turned along the arrow direction first, a surface potential of thephotoconductive drum 11 is uniformly charged at a fixed potential (forinstance, a minus charge) by the electrostatic charger 12. As a concretemethod of charging, a Scorotron method of charging, a roller method ofcharging, and a brush method of charging can be cited.

Next, a laser beam 13A is irradiated to the photoconductive drum 11 inresponse to an image signal by a laser generator and scanner 13 removingthe minus charge in the irradiated portion to form a charged image(electrostatic latent image) of a prescribed pattern on the surface ofthe photoconductive drum 11.

Then, charged metal-containing resin particles 2A stored in a developingmachine 14 are electrostatically attached on the electrostatic latentimage on the photoconductive drum 11 by means of a feeder to obtain avisible image. A dry or wet toner transfer technology in a well knownelectrophotography type copy system can be applied to the developingmachine 14.

When the developing machine is a dry type, the metal-containing resinparticles having a particle size from 3 to 50 μm are stored in thedeveloping machine 14. More desirable particle size of themetal-containing resin particles 2A is from 5 to 10 μm. On the otherhand, when the developing machine 14 is a wet type, the metal-containingresin particles 2A having a particle size of 3 μm or less are stored inthe developing machine 14 together with a liquid which serves as asolvent.

The metal-containing resin particles 2A stored in the developing machine14 are supplied to the photoconductive drum 11 by means of the feeder todevelop. At this time, a charged area development or a discharged areadevelopment can be used.

The metal-containing resin particles 2A are composed of a resincontaining 50 wt % or more of a thermosetting resin having a rate ofmoisture absorption from 500 to 14500 ppm and fine metal particlescontained in this resin. A rate of moisture absorption of the resin isdesirably from 4000 to 8000 ppm. The reason for determining the rate ofmoisture absorption of the resin to be from 500 to 14500 ppm is asfollows. If the rate of moisture absorption of the resin is less than500 ppm or more than 14500 ppm, the amount of electrostatic charge isbelow 5 μC/g being a lower limit of the electrostatic charge with whichan ordinary dry type copier is able to develop.

A thermosetting resin in a B-stage solid at room temperatures is used asa thermosetting resin to be contained in the resin. The B-stage refersto a state in which at least one portion of the thermosetting resin isnot hardened but melted when prescribed heat is applied. As thethermosetting resin in B-stage, epoxy resin, polyimide resin, phenolresin, bismaleimide resin, cyanate ester resin, bismaleimide-triazineresin, benzicyclobutene resin, polyimide resin, polybenzoxazol resin,butadiene resin, silicone resin, polycarbo-di-imide resin, polyurethaneresin and so on can be used.

For the fine metal particles, at least one kind of fine metal particlesselected from the group consisting of platinum (Pt), palladium (Pd),copper (Cu), gold (Au), nickel (Ni), and silver (Ag) is desirably used.These fine metal particles serve as kernels for electroless plating andhave a catalytic function for progress of a plating reaction. Amongthese metal elements, especially lead or copper is desirably used.

Then, the visible image (pattern) formed with the metal-containing resinparticles 2A on the surface of the photoconductive drum 11 iselectrostatically transferred onto a desired substrate 1 from thephotoconductive drum 11 by the copier 15. The photoconductive drum 11 isrecovered after the transfer by removing the metal-containing resinparticles 2A left on the surface of the photoconductive drum 11 with acleaning apparatus (not shown).

Then, the metal-containing resin particles 2A in B-stage, which aretransferred onto the substrate 1, are passed through the fixingapparatus 16 which emits heat or light, so that a thermosetting resincomposing the metal-containing resin particles 2A is melted to form ametal-containing resin layer 2B. Thereafter, the metal-containing resinlayer 2B is heated or irradiated with light by the fixing apparatus 16to be hardened so that the metal-containing resin layer 2B is fixed onthe substrate 1. Through these processes, an underlying layer 2 isformed.

After forming the underlying layer 2 on the substrate 1, a plating layer3 is formed on the underlying layer 2 by electroless plating using thefine metal particles contained in the underlying layer 2 as kernels asshown in FIG. 2B(step 2). It should be noted that though the platinglayer 3 is formed by electroless plating in the present embodiment, theplating layer 3 can be formed by both of electroless plating andelectroplating.

In order to effectively perform the electroless plating, it isrecommendable to treat at least some of the fine metal particles toproject on the surface of the underlying layer 2 before performing theelectroless plating to the underlying layer. As such a treatment, forinstance, etching with a solvent such as aceton, isopropanol acid oralkali or the like, or shot blasting, airblasting and so on can becited.

After forming the plating layer 3 on the substrate 1, an electricallyinsulative insulating layer 4 is formed on the substrate 1 as shown inFIG. 2C by printing using the electrophotography (step 3). Theinsulating layer 3 can be formed using an insulating layer formingapparatus 20 nearly similar in structure to the underlying layer formingapparatus 10. Here, the insulating layer forming apparatus 20 is placedin the room R having relative humidity of 70% or lower. A resin particle4A is stored in the developing machine 14 in place of themetal-containing resin particle 2A as shown in FIG. 4.

In order to form the insulating layer 4, first, while a photoconductivedrum 11 is turned along the arrow direction, a surface potential of thephotoconductive drum 11 is uniformly charged at a fixed potential (forinstance, minus charge) by an electrostatic charger 12.

Next, after charging the surface of the photoconductive drum 11, a laserbeam 13A is irradiated to the photoconductive drum 11 in response to animage signal by a laser generator 13 removing the minus charge in theirradiated portion to form a charged image (electrostatic latent image)of a prescribed pattern on the surface of the photoconductive drum 11.

After the electrostatic latent image is formed on the surface of thephotoconductive drum 11, the resin particles 4A which are charged by thedeveloping machine 14, are electrostatically attached on the surface ofthe photoconductive drum 11 to form a visible image on the surface ofthe photoconductive drum 11 (step 33). A dry or wet toner transfertechnology in a well-known electrophotography copying system can beapplied to the developing machine 14.

When the developing machine 14 is a dry type, the resin particles 4Ahaving an average particle size from 3 to 50 μm are stored in thedeveloping machine 14. The more desirable particle size of the resinparticle 4A is from 8 to 15 μm. On the other hand, when it is a wettype, the resin particles having a particle size of 3 μm or less arestored together with a liquid being the solvent in the developingmachine 14. When forming the insulating layer 4, it is desirable for theinsulation layer to have a thickness to some extent in terms of electricinsulation, and therefore, the particle size of the resin particle 4A isdesirably larger than that of the metal-containing resin particle 2A.

The resin particles 4A stored in the developing machine 14 are suppliedto the photoconductive drum 11 by a feeder to be developed. At thistime, a charged area development or a discharged area development can beused.

The resin particles 4A are composed of resin containing 50 wt % or moreof a thermosetting resin, having the rate of moisture absorption from500 to 14500 ppm. The rate of moisture absorption of the resin isdesirably from 4000 to 8000 ppm. The reason for determining the rate ofmoisture absorption of the resin to be from 500 to 14500 ppm is asfollows. If the rate of moisture absorption of the resin is less than500 ppm or more than 14500 ppm, the amount of electrostatic charge comesto be below 5 μC/g being a lower limit of the electrostatic charge withwhich an ordinary dry type copier is able to develop.

A thermosetting resin in a B-stage solid state at room temperatures canbe used as a thermosetting resin to be contained in the resin. As thethermosetting resin in B-stage, epoxy resin, polyimide resin, phenolresin, bismaleimide resin, cyanate ester resin, bismaleimide-triazineresin, benzicyclobutene resin, polyimide resin, polybenzoxazol resin,butadiene resin, silicone resin, polycarbo-di-imide resin, polyurethaneresin and so on can be used. It is also recommendable to disperse fineparticles of silica or the like contained in the resin particles 4A at aprescribed ratio, thereby enabling to control the characteristics suchas stiffness, coefficient of thermal expansion and the like especiallyin a multilayer wiring substrate, so that improvement in reliability ofsubstrate can be realized.

After the visible image (pattern) is formed on the surface of thephotoconductive drum 11, it is electrostatically transferred onto thedesired substrate 1 from the photoconductive drum 11 by the copier 15.The photoconductive drum 11 after the transfer is recovered by removingthe resin particles 4A left on the surface of the photoconductive drum11 with a cleaning apparatus (not shown).

After the visible image is transferred onto the substrate 1, the visibleimage is heated by the fixing apparatus 16 to soften the resin particles4A composing the visible image so that a resin layer 4B is formed. Then,the resin layer 4B is hardened by heat or light irradiation with thefixing apparatus 16 to fix the resin layer 4B on the substrate 1 (step35). Through the above process, the insulating layer 4 composed of theresin layer 4B is formed.

After forming the insulating layer 4 on the substrate 1, the electroniccircuit forming process from step 1 to step 3 is repeated to form amultilayered electronic circuit substrate 5 such as shown in FIG. 2D.

Since the metal-containing resin particles 2A composed of a resincontaining 50 wt % or more of a thermosetting resin and having the rateof moisture absorption from 500 to 14500 ppm, and fine metal particlescontained in this resin, are used in the present embodiment, the amountof charge of the metal-containing resin particles 2A can be controlledin an optimum range, so that the underlying layer 2 (metal-containingresin layer 2B) can be accurately formed.

Since the resin particles 4A composed of a resin containing 50 wt % ormore of a thermosetting resin and having the rate of moisture absorptionfrom 500 to 14500 ppm are used in the present embodiment, the amount ofcharge of the resin particles 4A can be controlled in an optimum range,so that the insulating layer 4(resin layer 4B) can be accurately formed.

Since the underlying layer 2 is formed in the room R where the relativehumidity is 70% or less in the present embodiment, the rate of moistureabsorption of the resin in the metal-containing resin particle 2A can bekept at 14500 ppm or less, so that the underlying layer 2(metal-containing resin layer 2B) can be accurately formed.

Since the insulating layer 4 is formed in the room R where the relativehumidity is 70% or less in the present embodiment, the rate of moistureabsorption of the resin particle 4A can be kept at 14500 ppm or less, sothat the insulating layer 4(resin layer 4B) can be accurately formed.

(EXAMPLE 1)

Hereinafter, example 1 will be explained. An optimum range of the rateof moisture absorption in the resin of the metal-containing resinparticle is studied in the present example 1.

In the present example, metal-containing resin particles composed of 50wt % resin and 50 wt % fine metal particles, having an average particlesize of 7.9 μm are used. Here, the resin is composed of epoxy resin onlyand the fine metal particles are composed of copper (Cu). A plurality ofmetal-containing resin particles different in rate of moistureabsorption are prepared and the amount of electrostatic charge at thetime when these metal-containing resin particles are charged ismeasured. Here, the rate of moisture absorption of the resin in themetal-containing resin particles is a value obtained by a calculation insuch a manner that the metal-containing resin particle is kept standingstill for two days in a vacuum environment while weighing the resinparticle. A state at which nearly no change of weight is recognized istaken as a dry state of the resin particle, and the rate of moistureabsorption is calculated by dividing a change in weight of the resinsince then with the weight of the resin in the dry state.

The result of the study will be described below. FIG. 5 is a graphshowing relations between the rate of moisture absorption of the resinin the metal-containing resin particle and the amount of electrostaticcharge of the metal-containing resin particle relating to the presentexample. As shown in FIG. 5, when the rate of moisture absorption is 458ppm, the amount of the electrostatic charge is 4.76 μC/g. This is due toexistence of a metal-containing resin particle which causes reversecharging. On the other hand, when the rate of moisture absorption is15424 ppm, the amount of charge is 3.52 μC/g. This is because theelectrical resistance on the surface of the metal-containing resinparticle is lowered, which makes the charging thereon difficult. Theamounts of electrostatic charge in either cases are below 5 μC/g, thevalue being a lower limit of the electrostatic charge with which anordinary dry type copier is able to develop. When determining the rangeof rate of moisture absorption to be 5 μC/g or more from this graph, itis found that when the rate of moisture absorption is from 500 ppm to14500 ppm, the amount of electrostatic charge becomes 5 μ/g or more.From this result, the optimum range in rate of moisture absorption ofthe resin in the metal-containing resin particle is confirmed to be from500 ppm to 14500 ppm.

(EXAMPLE 2)

Hereinafter, example 2 will be explained. In the present example, anoptimum range of the rate of moisture absorption in the resin particleis studied.

In the present example, resin particles composed of epoxy resin only,having an average particle size of 7.9 μm are used. A plurality of resinparticle samples different in rate of moisture absorption are prepared,and the amount of electrostatic charge at the time when these resinparticles are charged is measured. Here, the rate of moisture absorptionof the resin is a value obtained by a calculation in such a manner thatthe resin particle is kept standing still for two days in a vacuumenvironment while weighing the resin particle. A state at which nearlyno change of weight is recognized is taken as a dry state of the resinparticle, and the rate of moisture absorption is calculated by dividinga change in weight of the resin since then with the weight of resinparticle in the dry state.

The result of the study will be described below. FIG. 6 is a graphshowing relations between the rate of moisture absorption of the resinparticle and the amount of electrostatic charge of the resin particlerelating to the present example. As shown in FIG. 6, when the rate ofmoisture absorption is 443 ppm, the amount of the electrostatic chargeis 4.82 μC/g. This is due to existence of a resin particle which causesreverse charging. On the other hand, when the rate of moistureabsorption is 15320 ppm, the amount of charge is 4.10 μC/g. This isbecause the electrical resistance on the surface of the resin particleis lowered, which makes the charging thereon difficult. The amounts ofelectrostatic charge in either cases are below 5 μC/g, the value being alower limit of the electrostatic charge with which an ordinary dry typecopier is able to develop. When determining the range of rate ofmoisture absorption to be 5 μC/g or more from this graph, it is foundthat when the rate of moisture absorption is from 500 ppm to 14500 ppm,the amount of electrostatic charge becomes 5 μ/g or more. From thisresult, the optimum range in rate of moisture absorption of the resinparticle is confirmed to be from 500 ppm to 14500 ppm. The reason forthat the optimum range in the rate of moisture absorption of the resinof the metal-containing resin particle is the same as that of the resinparticle is as follows. Since 89% in volume of the metal-containingresin particle containing 50 wt % of copper (Cu) is resin, the surfacesof both resin are nearly equal, as long as the average particle size ofthe metal-containing resin particles is the same as that of the resinparticles.

(EXAMPLE 3)

Hereinafter, example 3 will be explained. In the present example, therelative humidity of an environment, at which the rate of moistureabsorption of the resin particle is 14500 ppm or less is studied.

In the present example, two kinds of resin particle samples composed ofepoxy resin only, having average particle sizes of 8.5 μm and 11.4 μmrespectively, are prepared, and the rates of moisture absorption of theresin particles when these resin particles are kept standing still inthe environment having relative humidity (R.H.) of 70% and 80%respectively are measured.

The result will be described below. FIG. 7 is a graph showing relationsbetween the time for standing still and the rate of moisture absorptionof the resin particle relating to the present example. As shown in FIG.7, it is confirmed that the rate of moisture absorption of the resinparticle is nearly saturated for about six hours without depending onthe average particle size, and becomes constant thereafter. Alsoconfirmed is that the rate of moisture absorption of the resin particlediffers depending on the relative humidity of the environment where theresin particle is kept standing still. More concretely, when the resinparticle is kept standing still in an environment at 70% R.H., the rateof moisture absorption becomes constant at around 14400 ppm, and whenthe resin particle is kept standing still in an environment at 80% R.H.,the rate of moisture absorption becomes constant at around 17300 ppm.From this result, it is confirmed that a resin particle having the rateof moisture absorption of 14500 ppm or less can be obtained when theresin particle is kept standing still in an environment at 70% R.H. Thesmaller the average particle size of the resin particles, the greaterthe surface area per unit mass becomes. Accordingly, though the resinparticles having an average particle size of 8.5 μm have the rate ofmoisture absorption about 50 ppm larger than the resin particles havingan average particle size of 11.4 μm, it is considered that anenvironmental relative humidity has a larger influence upon the rate ofmoisture absorption than the average particle size, there is nosignificant difference within a range of actual average particle sizesof the resin particles.

It should be noted that the present invention is not limited to thecontent of description in the above-described embodiment, structures,materials, arrangements of respective members, and the like can beappropriately modified within the meaning and range of equivalency ofthe present invention.

1. A metal-containing resin particle, comprising: a resin containing 50 wt % or more of a thermosetting resin, and having a rate of moisture absorption from 500 to 14500 ppm; and a fine metal particle contained in said resin.
 2. The metal-containing resin particle according to claim 1, wherein said resin has the rate of moisture absorption from 4000 to 8000 ppm.
 3. The metal-containing resin particle according to claim 1, wherein the thermosetting resin comprises a B-stage thermosetting resin.
 4. The metal-containing resin particle according to claim 1, wherein said fine metal particle is at least one kind of the fine metal particles selected from the group consisting of platinum (Pt), palladium (Pd), copper (Cu), gold (Au), nickel (Ni), and silver (Ag).
 5. A resin particle comprising: a resin containing 50 wt % or more of a thermosetting resin, and having the rate of moisture absorption from 500 to 14500 ppm.
 6. The resin particle according to claim 5, wherein said resin has the rate of moisture absorption from 4000 to 8000 ppm.
 7. The resin particle according to claim 5, wherein said thermosetting resin comprises a B-stage thermosetting resin.
 8. An electronic circuit substrate, comprising: a substrate; a metal-containing resin layer formed on said substrate, and formed by using the metal-containing resin particle according to claim 1; and a plating layer formed on said metal-containing resin layer by using said fine metal particle as a kernel.
 9. The electronic circuit substrate according to claim 8, further comprising: a resin layer formed on said plating layer and formed by using the resin particle according to claim
 5. 10. An electronic circuit substrate, comprising: a substrate; a plating layer formed on said substrate; and a resin layer formed on said plating layer and formed by using the resin particle according to claim
 5. 11. A method of producing an electronic circuit, comprising: forming a metal-containing resin layer in an environment at 70% or less of relative humidity, wherein said forming of the metal-containing resin layer comprises, forming a visible image on the surface of a photoconductor on which an electrostatic latent image is formed by electrostatically attaching said metal-containing resin particles composed of a resin containing 50 wt % or more of a thermosetting resin and having the rate of moisture absorption from 500 to 14500 ppm, and fine metal particles contained in said resin; and transferring the visible image composed of said metal-containing resin particles and formed on the surface of said photoconductor onto a substrate.
 12. The method of producing an electronic circuit according to claim 11, wherein said resin has the rate of moisture absorption from 4000 to 8000 ppm.
 13. The method of producing the electronic circuit according to claim 11, wherein said thermosetting resin comprises a B-stage thermosetting resin.
 14. The method of producing the electronic circuit according to claim 11, wherein said fine metal particle is at least one kind of the fine metal particles selected from the group consisting of platinum (Pt), palladium (Pd), copper (Cu), gold (Au), nickel (Ni), and silver (Ag).
 15. The method of producing the electronic circuit according to claim 11, further comprising: forming a plating layer on the metal-containing resin layer by using the fine metal particle as a kernel; and forming a resin layer to be performed in an environment at 70% or less of relative humidity, wherein said forming of the resin layer comprises: forming the visible image on the surface of the photoconductor on which the electrostatic latent image is formed by electrostatically attaching resin particles composed of the resin containing 50 wt % or more of a thermosetting resin and having a rate of moisture absorption from 500 to 14500 ppm; and transferring the visible image composed of the resin particles and formed on the surface of the photoconductor onto the plating layer.
 16. The method of producing the electronic circuit according to claim 15, wherein the resin in the resin particle has a rate of moisture absorption from 4000 to 8000 ppm.
 17. The method of producing the electronic circuit according to claim 15, wherein the thermosetting resin in the resin particle comprises a B-stage thermosetting resin.
 18. A method of producing the electronic circuit, comprising: forming a resin layer to be performed in an environment at 70% or less of relative humidity, wherein said forming of resin layer comprises, forming a visible image on a surface of a photoconductor on which an electrostatic latent image is formed by electrostatically attaching resin particles composed of a resin containing 50 wt % or more of a thermosetting resin and having a rate of moisture absorption from 500 to 14500 ppm; and transferring the visible image composed of the resin particles and formed on the surface of the photoconductor onto a substrate.
 19. The method of producing the electronic circuit according to claim 18, wherein the resin has a rate of moisture absorption from 4000 to 8000 ppm.
 20. The method of producing the electronic circuit according to claim 18, wherein the thermosetting resin comprises a B-stage thermosetting resin. 